نتایج جستجو برای: chronosequence
تعداد نتایج: 759 فیلتر نتایج به سال:
Current theories about vegetation succession and food web assembly are poorly compatible, as food webs are generally viewed to be static, and succession is usually analyzed without the inclusion of higher trophic levels. In this study we present results from a detailed analysis of ecosystem assembly rules over a chronosequence of 100 years of salt marsh succession. First, using 13 yearlong obse...
Research on the dynamics of biodiversity has progressed tremendously over recent years, although in two separate directions - ecological, to determine change over space at a given time, and evolutionary, to understand change over time. Integration of these approaches has remained elusive. Archipelagoes with a known geological chronology provide an opportunity to study ecological interactions ov...
Biological activity can accelerate soil processes and can thus have profound effects on weathering and the transformation of phosphorus (P). Here we show that the transformation of P is closely linked to soil development across an about 9000 years old soil chronosequence formed through glacial rebound. Easily weathered forms of P such as apatite are rapidly lost from the surface mineral horizon...
The chronosequence approach, which infers temporal patterns of environmental change from a spatial array of modern sites, has been a major tool for studying successional processes. A model of early lake ontogeny in boreal landscapes, developed from a chronosequence of lakes in Alaska, suggests that long-term soil development and related hydrological change produce a loss of alkalinity and base ...
Proper quantification of the relative influence of soil and plant host on the root-associated microbiome can only be achieved by studying its distribution along an environmental gradient. Here, we used an undisturbed salt marsh chronosequence to study the bacterial communities associated with the soil, rhizosphere and the root endopshere of Limonium vulgare using 454-pyrosequencing. We hypothes...
Abstract. Forest fires modify soil organic carbon and suppress respiration for many decades after the initial disturbance. The associated changes in autotrophic heterotrophic from time of forest fire, however, are less well characterized. FireResp model predicts parameterized with a novel dataset across fire chronosequence Yukon Northwest Territories Canada. consisted incubation experiments fie...
Green alder (Alnus viridis ssp. fruticosa) is a dominant understory shrub during secondary successional development of upland forests throughout interior Alaska, where it contributes substantially to the nitrogen (N) economy through atmospheric N2 fixation. Across a replicated 200? year old vegetation chronosequence, we tested the hypotheses that green alder has strong effects on soil chemical ...
The Hawaiian Islands offer a unique opportunity to test how changes in the properties of an isolated ecosystem are propagated through the organisms that occur within that ecosystem. The age-structured arrangement of volcanic-derived substrates follows a regular progression over space and, by inference, time. We test how well documented successional changes in soil chemistry and associated veget...
Specific leaf area (SLA) and leaf area index (LAI) were estimated using site-specific allometric equations for a boreal black spruce (Picea mariana (Mill.) BSP) fire chronosequence in northern Manitoba, Canada. Stands ranged from 3 to 131 years in age and had soils that were categorized as well or poorly drained. The goals of the study were to: (i) measure SLA for the dominant tree and understo...
This study explores the environmental forces controlling lake ontogeny at Glacier Bay as a model for early Holocene lake evolution in north temperate lakes worldwide. Long-term chemical and biological changes in lakes are investigated with two complementary research strategies: (1) limnological conditions are compared among 32 lakes of known age and in different stages of primary catchment succ...
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